Sewing machine



Dec 3, 1946- -J. l-LvPlKuL 2,411,977

` SEWING MACHINE Filed Feb. 21. 1944 '1 sheets-snaai 2 1NVEN+DRZ 4 .u. ma..

A-Hysmen 3, 1946.

J. H. PlKuL SEWING cams Fuga Feb. 21, 1944 '1 sheets-snaar s SEWING MACHINE Filed Feb. 21, 1944 '7 sheets-smet 5 Dec. 3, 1946. JQH. PIKUL SEWING MACHINE Filed Feb. 21, 1944 'I sheets-sheet 6 INVEN' da I LQ-942.

, Patented 3, 1946 I Joseph H. Pikul,

to The Reece Corporation,

Maine West Newton; Mass., assigner a corporation of Application February 21, 1944, serial No. 523,113 s claims. (01. 11a-197) This invention relates to machines for forming stitches in material.

Heretofore, when chain stitches were resorted to in machine sewing, it was necessary to terminate any group o-f continuous chain stitches with a conventional tying stitch in order to secure the entire group of stitches against unravelling.

An example of a sewing machine of this type is shown and described in my prior Patent No. 2,131,387, dated September 27, 1938. While a conventional tying stitch secures a group of chain stitches in a satisfactory manner, its formation by the same instrumentalities which form the chain stitches involves at least a diiierent operation of these instrumentalities, which complicates the machine and accordingly increases the cost of the same.

It is the primary aim and object of the present invention to make provision in a sewing machine for securing a machine-sewn group of continuous chain stitches against unravelling without resorting to a conventional tying stitch and without requiring a different operation of thev stitchforming instrumentalities of the machine.

The invention will be vmore from the following description in commotion with the accompanying drawings, in which:

Fig, 1 is a. greatly magnified bottom view of an.

piece of material holding a series of chain stitches which are secured against unravelling in accordance with the present invention.

Fig. 2 is a section taken substantially on the line 2-2 of Fig, l. and illustrates theconventional concatenation of the loops of a. chain stitch.

Fig. 3 is a section taken substantially on the line 3-3' of Fig. l. and showsan intermediate .step in securing the lastv stitch of a group of chain stitches against unravelling.

Fig. 4 is a section similar to Fig. 3, showing the last stitch completed.

Figs. 5 and 6 are sections taken substantially on the lines 5-5 and 6-6. respectively, ot Figs. 3 and 4, respectively.

Fig. '7 is a greatly enlarged, fragmentary sec` tional view of the stitch-securing mechanism of a machine embodying the present invention.

Figs. 8 and 9 are fragmentary sectional views similar to Fig.l '7, showing progressive steps in the operation of the mechanism in securing the last stitch of a series of chain stitches.

,Figs. 10 and 11 are fragmentary sections taken substantially on the lines Iii-l0 and |Il i, respectively, of Figs, 7 and 9, respectively. i

f Fig. 12 shows a modified element of the stitchsecuring mechanism of the machine.

clearly understood Fig. 13 is a greatly magnified section through a partly completed, securing stitch obtained withI the modied element of Fig. 12,'the section being similar to the section of Fig. 5.

Fig. 14 is a, section similar to Fig. 13, showing the secured stitch completed.

Fig. 15 is a greatly magnied illustration of a' straight seam of chain stitches secured against unravelling in accordance with'the present invention.

Fig. 16 is another greatly enlarged, fragmentary sectional view of a part of the stitch-forming mechanisms of the machine.

Fig. 17 is a fragmentary sectiona1 view similar to Fig. 16, showing modified structure for securing chain stitches against unravelling.

Fig. 18 is a fragmentary section taken substantially on the line i8-I 8 of Fig. 17.

Fig. 19 is a side elevation, partly broken away,

of the .machine which incorporates the stitch-` securing mechanism of the present invention.

Fig. 20 is a plan view, partly broken away, of the machine as shown in Fig. 19.

Fig. 21 is an end elevation, partly broken away, of the machine as viewed from the left in Figs. 19 and 20. Y

Fig. 22 is an end elevation of themachineas viewed from the right in Figs. 19 and 20.

Fig. 23 is an end elevation similar to Fig. 22,v

shown as arranged in zig-,zag fashion. The formation of the chain stitches is conventional, the

machine which may be used for this purpose-- providing a reciprocatory and laterally vibratory needle 3| (Fig. 21) and two loopers'32 whichalternately cooperate with the needle 3l in the formation of successive chain stitches. Fig. 7 illustrates a. step in the normal cooperation of the needle 3l and one of the loopers 32 in the formationof the chain stitches, the looper 32' having seized the thread loop l cast by the needle 3l on its preceding ascent through the hole -h in the material, and deflected it into the position shown in Fig. 'l in which said loop is in alignment with the needle in the left end position of its lateral vibration. A

After the machine has sewn a group of continuous chain stitches, the needle. 3l and the looper 32' will come to rest in the relative disposition shown in Fig. 'l withthe last loop l held on said looper. While the last loop l is thus heid on the looper 32', a blade or deector 33 below the throat plate 34 is linearly moved from the position shown in Figs. 7 and 10 into the position shown in Figs. 9 and 11 to deflect the diverging legs of said loop l. The defiector 33 is provided with a slot 35 (Fig. 10) of a width substantially equal to the thickness of the needle 'thread t, and a wedge-shaped notch 36 which leads int-o the slot 35. Hence, o-n movement of the deflector 33 from the position shown in Fig. '7 into that shown in Fig. 9, the two legs of the loop l are guided toward the slot 35 by the notch 35 and enter said slot one behind the other. In the present instance, the deector 33 is so coordinated with the looper 32' that the slot 35 in said deeotor is in line with the rear leg Zx of the loop l.

so that, on movement of said deflector from the position shown in Figs. 7 and 10 into that shown in Figs. 9 and 11, said leg Zx enters said slot 35 without engaging a wall of the V-shaped notch 36, While the front leg IY of the loop l is cammed into the slot 35 by the wall 36 of the V-shaped notch 36. Consequently, the rear leg lx of the loop Z will enter the slot 35 before the front leg ZY is cammed Athereinto, with the result that the portions of these legs which extend from the deiiector 33 substantially to the material W become `superposed with the front leg ly nearest the material W (Figs. 8 and 9). Since the loop Z is being dlstended while being deflected, and sincethe ecdle thread tension devices (to be referred to hereinafter) of the machine resist with considerable force the drawing of needle thread through the needle while the loop Z is being deiiected as described, the distending loop Z will,

draw thread from the preceding loop l' (Figs. 7 and 8) until the latter is drawn tight. The rear wall 38 of the slot 35 inthe deliector 33 is rounded as shown in Figs. 7 to 9 so as to avoid chaiing the thread of the distending loop l. In order to permit the contracting loop-Z to close as tightly as possible about the legs of the loop l when the latter is being distended (Figs. and 9), the deflector 33 brings the legs of the loop l preferably as closely as possible to the convergence C of the legs of the preceding loop l (Figs. 9 and 11).` To this end, the deiiector 33 is arranged to deflect the legs yoi. the loop l as closely as possible to the material W (Fig. 9), the del'iected legs of the loop being received in a cutaway portion 39 of the throat plate 34. To the same end, the deiiector 33 is moved in such a direction that the legs oi' the loop l between the deector and the material (Fig. 11) pass the convergence C of the legs of the loop l' as closely as possible so that said loop l' may contract into i'lrm ,wedging engagement with the legs ,of the loop l without undue restraint from the latter. The contracting loop l', through intermediation of the legs lX and ZY of the loop l. also draws the loop l", which immediately precedes the loop l',

rmly against the material W (Figs. 3 and 9). Shortly before the deflector 33 reaches the most advanced position shown in Fig. 9, the same brings the rear leg lx of the loop l into engagement with a knife 40 on the looper 32' (Figs. 9 and 11), whereupon said leg is severed as at 4|. On subsequent removal of the material W from the machine, the severed portion of the loop l which is continuous with the needle thread is withdrawn from the material, leaving the severed rear leg lx of said loop l anchored between the loops l' and l" (Figs. 4 and 6).

The pull exerted by the distending loop l on 4 the thread of the preceding loop l' is so great that the thread of said loop l as well as of the loop l' is stretched within the llimit of its resiliency, and the contracted loop l draws the loop l against the loopl with such force that the engaged portions of said loops are considerably deformed and constricted (Figs. 3 and 5). The -thread of the contracted loop l' is in fact stretched to such an extent that the withdrawal therefrom of the severed end of the loop l does not cause any noticeable relaxation of its rm grip on the remaining portion of the severed loop l, the loop l' having suflicient resiliency to contractand hold the adjacent portion of the remainder of the severed loop l deformed and constricted as shown in Figs. 4 and 6. That the loop l' is under permanent tension and does not noticeably relax its firm grip on the severed loop l, even after the withdrawal of the severed end thereof, is evidenced by a very marked crosssectional constriction of the leg lx between the loop l' and the material W (Fig. 4) as observed under a microscope. As also observed under the microscope, the cross-over leg lz of the last stitch is partly embedded in the material W (Fig. 4) in consequence of the permanent tension in the thread of said last stitch. The tied chain stitch shown in Figs. 4 and 6 has deed all ordinary efforts to unravel or even .loosen the same, wherefore said stitch serves as, and is in fact, a novel tying stitch which is as well secured against unravelling as. a conventional tying stitch.

Whereas the described deilector 33 has a provision (narrow slotI 35) for forcing the deflected legs of the loop l into superposed relation along the material W (Fig. 9), a modified deflector 45 (Fig. 12) merely forces the diverging legs of the loop l together. To this end, the defiector 45 has a wedge-shaped notch 46 the bottom 41 of which.

is rounded. On movement of the defiector 45 in the direction of the arrow 48 in Fig. 12, the diverging legs of the loop l on the looper 32' will, besides being deected, also be forced into sideby-side engagement with one another by the rounded bottom 41 of the notch 46, resulting in the disposition of the legs of loop l in the contracted loop l' as shown in Fig. 13. After severance of the 4loop l and withdrawal of the severed end thereof from the contracted loop l', the remaining end of the severed loop is wedged against the contracted loop l' (Fig. 14) and against the preceding loop l" in much the same fashion as shown in Figs. 4 and 6.

Fig. 15 shows the novel tying `stitch applied at the end of a straight seam of chain stitches 50, the contracted loop 5I of the last stitch firmly wedging the remaining end 52 of the last severed loop against the loop 53 which immediately precedes the loop 5i. In view of the preceding, detailed description of the formation of the novel tying stitch at the end of a zig-zag seam of chain stitches, the yformation of the. same tying stitch at theend of a straight seam of chain stitches is too obvious to require further explanation.

Figs. 16 and 17 disclose a modified mode of tying the last one of a series of chain stitches. The machine used for forming these stitches may be -like the one used for forming the stitches 30 in Fig. l, and comprise a reciprocatory and vibratory needle (not shown) carrying needle thread t, and a pair of alternately operative loopers of which one is shown at 55. After the sewing instrumentalities of the -machine come to rest with the needle retracted and the looper 55 in the position shown in Fig. 16 and holding the last lloop 58, a. deector 51 unde-neath the throat plate 58 is moved in the direction of the arrowy58 in Fig. 18 to deflect thefront leg 56 in the manner best shown in Fig. 17, thereby distending the loop 56. The deflected leg 56' of the distending loop 56 forces the preceding loop 60 against the material W and the convergence of The distending loop 56, being unable to draw needle threadthrough the needle thread tension devices (not shown)l of the machine, must' draw thread from the preceding loops'60 and 6 I. Since the loop 68 is prevented from contracting by the deflected leg 56 of the last loop 56 (Fig. 17), the latter will draw thread from the loop 6| which immediately precedes the loop 60. The ensuing contraction of the loop 6| draws the loop 60 into firm wedging engagement with the material W arid the convergence of the legs of the loop 56 and at the same time forces said loop 6| toward the convergence of the legs of the last loop 56 (Fig. 17), so that, after-severance of the last loopv 56 and withdrawal of the severed end of said loop from the material, the ,end of the severed loop remaining in the materialis held fairly securely between the loops 60 and 6|. T he deflector 51 the legs of the loop 56.

has preferably an inclined cutting edge 62 (Fig.

18) which engages and severs the rear leg 56" of the loop 56 as at 63 when the front leg 56 thereof is deflected as shown in Figs. 17 and 18. A last stitch tied in `this fashion, while not at firmly secured as the previously described stitch shown in Fig. 4, for instance, is nevertheless satisfactory for many purposes.

Figs. 19 and 20 show an example of e. machine which may be equipped with mechanism to form the novel tying stitch shown in Figs. 4 and 6, for instance. This machine is a button hole sewing machine of the type known as straight hole machine, described, for example, in Patents Nos. 714,284, November 25, 1902; 749.776, January 19, 1904; 1,088.652Februari' 24 1914; 1.402.073, Jan'- uary 3, 1922; and 1.483.307, February 12, 1924. The machine comprises a bed 65 from which rises a standard 86, carrying an overhanging arm 61 spaced above the bed. The material or work W is carried by a work clamp or holder comprising a clamp plate 68 and cooperating clamping arms 68, said work holder being movable as a unit over the bed, by mechanism not shown, in order to position the stitches along the sides of the'buttonhole. The stitch-forming instrumentalities comprise the previously mentioned, eye-pointed needle 3| above the work and cooperating loopers or equivalent under thread handling devices 32 below the work, the throat plate 34 being .carried by the bed 65 andhaving an opening 10 through which the needle operates. The needle 3| is car-- ried by a needle bar 1| which is longitudinally and vertically reciprocated, by means generallyindicated at 12, in a needle bar guide 13, means (not shown) being provided for oscillating said needle bar alternately in opposite directions transversely to the direction of feed of the work clamp be-r tween successive strokes of the needle to position the depth stitches. The,l thread -t from a suitable source passes, through a take-up 14 and suitable tension devices 15 and 16, to the needle eye, whence it passes through the work and throat. plate to the loopers 32. The thread tension device 15 may be a thread -clamp which is preferably closed during the setting of the laststitch so. as to cause the tying of the last stitch with a maximum force. A main shaft 11, journalled in suitable bearings in the bed, has power applied theref a'belt shifter 8|.

f f 6 to by a belt 18 alternatively engageable with fast and loose pulleys vThe belt shifter 8| constitutes an extension of a stop member or arm 82 carried by an oscillating and longitudinallymovable rock shaft 83, mounted for oscillation and limited iongitudinai movement in the bed 65. Slidably mounted in the stop arm 82 is a stop element or bolt 84, normally urged toward the right in Figs. 22 and 23 by a springy 85. At its end the bolt 84 is formed with a nose 86 which, when the shaft 83 "is in theI longitudinal position to cause the belt shifter 8| to engage the belt 18 with the loose pulley 80, is in the path of movement of a'cam 81 (Figs. 22 and 23)which is fast on the shaft 11, said cam having a concentric portion a, a rise b, a notch c and a stop shoulder d, arranged to-engage the nose 86 in the order named when the shaft is rotated in the direction of the arrow 88 in Figs. 22 and 23. The nose 86, when in the path of movement of the cam 81, is heid in en gagement with the periphery of the latter by a spring-pressed plunger 88 carried by the upright 66 and engaging the stop arm 82, rsaid `plunger tending to turn said arm and the rock shaft 83 in aclockwise direction as viewed in Figs. 22 and 23, and thereby press the nose. 86 against the periphery of the cam 81.

A buttonhole cutter journalled on a short stud shaft 82 supported in the bed, said lever having an arm 83 carrying at its end a sleeve'94 in'which is journalleda stud 95, having at one end a sleeve portion 86 which receives a stud 81 extending inwardly from the stop arm 82.

The construction, arrangement and mode of operation of the parts above referred to, and certain associated parts, are, or may be, substantially as more fully described in the above-mentioned patents. Associated with the sliding rock shaft 83 is a spring |00 (Fig. 20) surrounding said shaft and interposed between a collar |0| thereof and one of the bearing brackets or ears |02 in which said shaft is mounted, said spring tending f 'normally to move said shaft toward the right in Fig. 20 into the position shown in the drawings, in

which the belt 18 is engaged with the loose pulley 80 and the nose 86 of the stop bolt 84 is in the pathV of-movement of the cam 81. To start thev machine, a starting lever |08 is operated to move the shaft 83 toward the left in Fig. 20, thereby shifting the belt 18 from the loose pulley 80 to the fast pulley 18 and moving the nose 86 out of the path of movement of the cam 81, said shaft being retained in this position by engagement of a detent |04 with a recess |05 therein. The detent |04 is lcontrolled by mechanism (not shown) associated with the feeding means for the work clamp and adjustablel in accordance with the length of the button hole to be sewn, the arrangement being such that just before the conclusion of the sewing cycle, and at about the beginning of the last stitch-forming cycle, the detent |64 is withdrawn from the notch |05, whereupon the spring |00 causes the shaft 83 to be restored to its normal position, thereby shifting the belt18- from the fast pulley 18 to the loose pulley 80 and bringing the nose 86 into the path of movement of the cam 81. During the formation of the last stitch, the machine runs under its own momen- 'tum and the nose 86 follows the periphery of the cam 81. -As said nose is engaged by the rise y b of said cam, the stop arm 82 is lifted against the action of the spring-pressed plunger 88 into the position shown in Fig. 23. This lifting of the stop -18 and 80 under the control of is carried by a lever 8|..

, shown in Fig. 21.

arm 82 operates, through the stud 31 and its connection with thearm' 93 of the lever 9|, to advance or depress the button hole cutter Il 'and cause the same to cut the button hole slit. Thereafter, the nose 36 drops on of the rise b oi' the cam 31 and, under the influence of the spring-pressed plunger 89, enters the notch c as shown inFig. 22, this movement causing the button hole cutter 90 to be retracted or raised to its original normal position. The nose 36 is thereupon 'immediately engaged by the stop shoulder d, thereby positively stopping the machine at the completion oi' the final stitch, the stopping impact being cushioned by a yielding of the bolt 84 toward the left in Fig. 22 against the compression the spring BI. In accordance with the present invention, a loop deflector such as the deector 33 in Figs. 9 and 10, for instance, is guided in ways in the bed 65 immediately below the throat plate 34 and between the latter and the loopers 32 (Figs. 19 and 21). At the completion oi the last stitch-forming cycle, and substantially coincidentally with the stopping of themachine, said deflector 33 is moved, by means to be described, from its normal retracted position shown in Fig. 20 in the direction of the arrow I I in said gure to deflect, and

thereby distend, the last loop l which. at this time is held by one of the loopers 32 and extends from the work W about said looper to the needle 3| as The deilection and simultaneous distention of the loop l by the deilector 33 results in the setting of the last stitch in the manner previously described and shown in Figs. 3 and 5. The looper which holds the last loop l also preferably carries a knife or cutter 40 which may be like the cutter 40 on the looper 32? in Fig. 9 and severs the rear leg of the loop l toward the end of its distention by the deilector 33. On subsequent removal of the material W from the machine and according withdrawal of the severed end of the loop l from the material, the last stitch is completed, and this stitch is the same as, and has all the`described characteristics of, the novel tying stitch shown in Figs. 4 and 6.

The deilector 33 is provided with a socket III (Fig. 21) to receive a rounded end H2 of an arm H3 which is fast on one end of a rock shaft III,

4arm III lsallnk III ill secured to the stop bolt .iournalled in suitable bearings in the bed Il and having secured to its opposite end an arm Hl (Figs. ilo and 22). Pivotally connected to the guided on the outer side of the bed 6l on a screw I I'I projecting from said bed and received in a slot lll in said link. At its other end the link Iltis formed with a' notch Ile adapted to be enteredby a ngse |29 on a collar When the nose 88 of the stop bolt I4 enters the notch c in the cam 31 under the iniluence or the spring-pressed plunger 89, as above explained and as shown in Fig. 22, the nose |20 enters the notch H9. Thereafter, when the stop bolt 84 yields under the impact of the shoulder d onthe nose I6, the link H6 is moved toward the left as viewed in Fig. 22, thereby turning the` shaft IM and operating the defiector 33 as described.

The above described tying stitch and method of making the same are not claimed herein, being covered by the claims of a divisional application Serial No. 553,527, tiled September 11, 1944.

I c aim:

1. In a. sewing machine, the combination with support, a reciprocatory needle and a a work looper cooperating therewith in the formation oi chain stitches in material, of a member between said looper and the work support movable from adjacent a first thread loop held on:r

said looper toward and beyond the immediately preceding, spaced thread loop in the material and adapted Aengage and deflect both legs of said first loopto distend the same so that said immediately preceding thread loop is drawn toward the material and into wedging engagement withthe legs of said rst loop.

2. 'I'he combination in a sewing machine as set forth in claim l, in which said member has a. V-shaped notch to engage and force together the diverging legs of said first loop.

3. The combination in a sewing machine as set` forth in claim 1, in which said member has a slot of a width substantially equal to the thickness of the thread and a V-shaped notch leading into said slot and adapted to engage and force the diverging legs of said first loop into said slot.

' I JOSEPH H. PlKUL. 

